The reforming of petroleum raw materials is an important process for producing useful products. One important process is the separation and upgrading of hydrocarbons for use as a motor fuel, or upgrading the octane value of the naphtha in the production of gasoline. However, hydrocarbon feedstreams from a raw petroleum source also include useful chemical precursors for use in the production of plastics, detergents and other products.
The upgrading of gasoline is an important process, and improvements for the conversion of naphtha feedstreams to increase the octane number have been presented in U.S. Pat. Nos. 3,729,409, 3,753,891, 3,767,568, 4,839,024, 4,882,040 and 5,242,576. These processes involve a variety of means to enhance octane number, and particularly for enhancing the aromatic content of gasoline.
While there is a move to reduce the aromatics in gasoline, aromatics have many important commercial uses. Among them are the production of detergents in the form of alkyl-aryl sulfonates, and plastics. These commercial uses require more and purer grades of aromatics. The production and separation of aromatics from hydrocarbons streams is, therefore, increasingly important.
Processes include splitting feeds and operating several reformers using different catalysts, such as a monometallic catalyst or a non-acidic catalyst for lower boiling point hydrocarbons and bi-metallic catalysts for higher boiling point hydrocarbons. Other improvements include new catalysts, as presented in U.S. Pat. Nos. 4,677,094, 6,809,061 and 7,799,729. However, there are limits to the methods and catalysts presented in these patents which can entail significant increases in costs.
Improved processes are needed to reduce the costs and energy usage in the production of aromatic compounds.